Apparatus and method for tractor cab environment control system

ABSTRACT

A tractor cooling system for chilling the cabin of a trucking tractor vehicle towing a refrigerated trailer. The cooling system is a closed loop recirculation system that utilizes a high thermal conductivity heat exchanger that isolates chilled air and through flexible hoses that supply and return forced air at a constant volume and thereby providing comfort to the driver during warm weather and without idling the engine and while stationary.

FIELD OF THE INVENTION

I have invented an energy efficient implementation for interior climate control cooling, for trucking vehicle combinations, and with particular reference to an apparatus by which the cabin of a transport trucking tractor can be chilled by heat exchange between said cabin and in combination with an attached operating refrigeration unit trailer used in highway transportation of perishable goods in the freight trucking and transport industry.

BACKGROUND OF THE INVENTION

Traditionally, during rest or sleep periods, maintaining the trucking tractor cab climate control for the comfort of the driver, has generally required continuously idling the engine in place, in order to run the on board interior air conditioning system to provide climate comfort during sleep or rest. Across the trucking industry nationally, idling the engine in place consumes millions of gallons of fuel annually in addition to generating harmful emissions.

SUMMARY OF THE INVENTION

The principal object of this invention resides in the provision of a forced air circulating system, consisting of a blower motor to force the circulation of air, powered by a dedicated independent deep discharge battery, electronic control for battery condition monitoring/charging functions and electronic control to control fan speed; the air circulating unit having flexible detachable hoses for continuous supply and return air at a constant volume, and a closed loop heat exchanger, manufactured of finned aluminum tubing and conductive means, adapted to be mounted on the front interior wall of a conventional refrigerated transport trailer whereby chilled air from said closed loop heat exchanger can be efficiently circulated at a constant volume and temperature, between the cab of a truck tractor and refrigeration truck trailer. Preferred embodiments and the benefits of heat exchangers versus prior art are discussed further hereunder.

Today there are millions of combination truck tractor cabs and refrigerated trailers conventionally used in the freight trucking industry for transporting perishable goods, such as meat, produce, dairy products, floral and many other commodities, and said trailers come readily equipped with automatic refrigeration units by which the temperatures inside are maintained at desired chilled levels. The interior refrigeration for the trailer is provided by conventional type cooling coils which are usually mounted in the forward end of the insulated trailer and chilled by a refrigerant acted on by a compressor installed in a suitable housing on the exterior of the trailer and on the front wall thereof.

For many years now, there has been a global push to reduce carbon-based emissions by either reducing the intake of carbon based fuels and reducing the output of harmful components by engines burning those fuels. In addition, from at least a fiscal perspective, most trucking carriers have financial motivation to retrofit systems on their existing trucking fleets, thereby reducing fuel intake in view of the realities of increasingly high fuel costs. In fact, much of the fuel used by carriers isn't in revenue generating miles. On average, 44% of the engine time is idling, in order to keep a driver comfortable during sleeping hours and rest periods. This engine idle time is not only expensive, it adds additional wear and tear on the truck tractor engine as well.

In addition to the foregoing, statutory regulations prohibiting idling the tractor cab engine, during periods of sleep or rest are sweeping the country affecting over 7 million trucks on the road nationally. The constant idling of the tractor trailer engine while stationary is now illegal. See United States Environmental Protection Agency “Model State Idling Law” at

http://www.epa.gov/smartway/documents/420s06001.pdf or American Transportation Research Institute “Compendium of Idling Regulations” at

http://www.atri-online.org/research/idling/atri_cabcard7_(—)11_(—)08.pdf

Because of these factors, some solutions have been brought to the market and utilize one or more of the following technologies:

Auxiliary Power Units (APUs) are smaller, efficient motors that provide a power source for both heating and cooling elements for the cab. APUs provide plenty of power to not only provide heating and cooling, but also to run additional items such as televisions, small microwave ovens and other conveniences without fear of running down the main engine batteries. However, APUs are generally the most expensive option and often have service intervals that occur more often than the trick tractor, thus increasing maintenance costs and down time for a fleet. Drivers also complain about the noise and vibration generated while the APUs are running, which can lead to additional driver discomfort and fatigue.

Battery powered systems can provide cooling and heating for a tractor up to a certain limit of actual cooling and circulation. The batteries are charged while the tractor engine is on. These systems are generally quieter and have very little maintenance costs. However, the power available to these systems may not be adequate for the more extreme weather temperatures.

Energy storage systems are related to the battery powered systems since they store the energy produced while the engine is on and then utilize that stored energy when the engine is off. One product uses cold air from the engine air conditioner while the truck is in motion to pre-cool a chemical solution. It is then passed through an evaporator coil to cool the air flowing into the cab. These systems utilize power from the engine that is already running. However, for extreme temperatures, the stored energy might not be sufficient for the entire sleeping time.

A prime object of this invention is that of providing an apparatus by which a provision of a closed loop chilled air circulating unit, having detachable flexible hoses for forced air pressure at a constant volume as well as supply and return air circulation between the truck tractor cab and refrigerated trailer, and a closed loop heat exchanger within the refrigerator trailer, where said continuously chilled circulating air can be transmitted to and from the cab of the towing tractor for the comfort of the operator at a constant volume, and to afford means by which the device can be readily connected between the refrigeration trailer and trucking tractor or detached as desired by twist lock flanges when not in use.

The key novelty in this circulating system is a closed loop heat exchanger that does not draw chilled air directly from the interior of the refrigeration trailer. Air is chilled by circulating it through a heat exchanger manufactured out of a metal material with high thermal conductivity, such as finned aluminum that possesses as a principle characteristic, superior thermal conductivity for thermal transfer. Said heat exchanger is located at or near the existing refrigeration unit located at the interior front wall of the refrigerator trailer. Chilled air is forced into the cab, carried by a detachable flexible hose from the heat exchanger located in the refrigeration trailer and continuously re-circulating air to and from the heat exchanger by a flexible hose to be chilled at a continuous temperature and at a continuous volume. U.S. Pat. No. 3,211,076, U.S. Pat. No. 5,253,700, U.S. Pat. No. 5,438,842, and US Patent Application 2006/0150653 all disclose methods of drawing chilled air from the trailer to the tractor cab to achieve a similar effect. U.S. Pat. No. 3,211,076 discloses a method of drawing chilled air from the interior of a refrigeration trailer into a trucking tractor vehicle utilizing a single flexible hose. It is not recirculating at a constant temperature or volume. U.S. Pat. No. 5,253,700 likewise also draws chilled air directly from the interior of the refrigeration trailer. While U.S. Pat. No. 5,438,842 is also drawing chilled air from the refrigeration trailer, it makes reference to the use of a commercially available charcoal filter. Depending upon the commodities to be shipped, aggressive odors and smells and undesirable air particulate accumulate inside the refrigeration trailer. The accumulation of odors from perishable goods, such as meat, produce, dairy products, floral products and many other commodities is undesirable for the comfort of the driver. The improvement and implementation of recirculating truck tractor cabin air through a closed loop heat exchange will provide and maintain a consistent quality of chilled air without any unpleasant odors or smells that would be present in prior art. It will not require an activated charcoal filter to abate odors from the perishable goods transported in the refrigeration trailer.

For trucking fleets that utilize refrigerated units, there is already an efficient source of power and cooling system already in place to preserve freight contents. While these units are used to cool approximately 3,700 cu ft. of trailer space, a closed loop system including a heat exchanger can be continuously recirculated between the cab of the tractor and the interior of the refrigeration trailer, providing cool air for the driver to utilize while the tractor engine is off.

A deep discharge battery source would be used to power a fan blower motor that by air pressure, forces, draws and recirculates the supply and return of the continuously recirculating air through the overall cooling system at a constant volume. The battery that powers the fan blower motor would be charged while the tractor and trailer are in transport operation.

The system is to be conveniently connected between the tractor cab and refrigerator trailer via flexible air hoses and quick connect hardware such as twist lock flanges. When detachable hoses are not in use and stowed away for safe keeping vehicle connection openings would be equipped with protecting twist locking covers. The flexible air hoses will channel the supply and return air for the chilled air system.

Electronic monitoring and charging circuits will service a dedicated deep discharge battery system to be incorporated into the installation for the purpose of independently powering the system while the tractor cab is parked and turned off. Overall, the modifications to the tractor cab and refrigeration trailer will be minimal. Input and return openings for the supply and return air will need to be retrofit at the rear exterior wall of the tractor cab and the front exterior wall of the refrigerator trailer. A control module will also be installed in the cab, enabling the driver to control the on/off state of the system as well as fan speed.

The trailer will need two retrofitted twist lock flanged openings for the supply and return air. Another retrofit modification is the mounting of the new heat exchanger adjacent to the existing interior refrigeration unit in said refrigeration trailer.

This solution provides a new closed loop cooling source to maintain a comfortable cab environment as opposed to directly drawing air to and from the internal environment of the refrigeration trailer, while utilizing already existing refrigeration and chilled air sources, thus reducing carbon emissions during driver rest periods. By utilizing existing resources as well as simple components, this will help to keep the overall cost of the system low, providing a quick return on investment from fuel savings and idle wear and tear for any user installing the system in their fleet.

The invention contemplates the provision of apparatus of simple and economical design and structure, which is easily adaptable to installation in any type of refrigerated transport trailer where it is desirable to provide chilled air to the interior of a tractor cab without having to idle the tractor engine while stationed.

While the foregoing objects are paramount, other and lesser objects will become apparent as the description proceeds, when considered in connection with the appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration, a cutaway, of the interior view of a trailer having a refrigeration unit installed in the forward end thereof, and showing the closed loop heat exchanger component of the air circulating unit of the invention mounted therein.

FIG. 2 is an illustration, a cutaway, viewing from top perspective, the invention installed in combination between the tractor truck cab unit and the refrigerated trailer unit.

FIG. 3 is an illustration, elevation view of the of the heat exchanger assembly indicating a plurality of finned aluminum tubing between supply and return tubes.

FIG. 4 is an illustration of the back wall of the tractor cab showing the sleeper duct and air distributor panel.

FIG. 5 is a simple single line diagram of the circulating air flow of the system between the tractor cab and the refrigeration trailer.

DETAILED DESCRIPTION OF THE INVENTION

Conventional refrigeration equipment implemented to preserve perishable goods within trucking transport trailers 3, of the type drawn by tractor cab 12, along the long distance public highways, usually comprises a bank of refrigeration coils (not shown) contained within a refrigeration housing 1, supported on or near the top of interior front wall of the refrigeration trailer 3, which has insulation material between the inner and outer walls, as shown in FIG. 2. The refrigerant is circulated through the coils by a compressor having a motor (not shown) which is enclosed in an exterior housing 8, attached to the exterior front wall of the trailer 3, as shown in FIGS. 1, 2 and 4.

The existing interior refrigeration housing 1, is generally and preferably placed well up on the inner front wall near the ceiling, as best shown in FIG. 2, and has an elongated outlet duct arranged along its inner wall 7, whereby refrigerated air is discharged along the ceiling longitudinally of the trailer by an exhaust fan within the refrigeration housing 1.

As shown in FIG. 2 and FIG. 3, a heat exchanger assembly 6, is constructed of an efficient thermally conductive metal material such as finned aluminum tubing 16, and mounted in a plurality of rigid construction tubes in parallel frame, coupled to rigid pipe 4, diverting said chilled circulating air through rigid pipe 4A and flexible hose 9; and framed by rigid pipe 2, coupled to rigid pipe 2A and flexible hose 10, capturing warm air into the heat exchanger assembly 6, and installed adjacent to the interior refrigeration housing 1, where ample amount of ambient chilled air continuously flows over the heat exchanger assembly 6.

Warm air enters the heat exchanger assembly 6, drawn by air pressure through the heat exchanger blower motor inside the blower and battery box 13. Air from the tractor cab 12, first enters through flexible hose 10, drawn through said blower motor in battery and blower box 13 and output to flexible hose 11 and to rigid pipe 2A coupled to heat exchanger assembly rigid pipe 2. Chilled air exits the heat exchanger assembly 6, through a rigid pipe 4, forced by said air pressure through rigid pipe 4A, coupled to flexible hose 9, and is circulated to the air distributor 15, installed inside tractor cab 12. To protect the heat exchanger assembly 6, from loading and unloading and shifting freight in transit a heat exchanger guard 5, covers the assembly.

The blower motor located in blower and battery box 13, is adapted to be attached to the end of twist lock flexible hose 11. The other end of flexible hose 11, connects to the front wall of the refrigerator trailer 3. The blower motor in blower and battery box 13, is further adapted to be attached to the twist lock of flexible hose 10. Flexible hoses 9 and are connected thereto whose opposite ends connected the refrigerator trailer front exterior wall and the tractor cab rear exterior wall via the twist lock disconnects.

While the structural details of the retrofit coupling to be implemented the trailer 3, and the tractor cab 12, is not of great importance to the invention, it is desirable that these openings through the walls, should be cylindrical and of such length only as to extend through the front wall of the refrigerator trailer and rear wall of the tractor cab and be provided with suitable twist lock disconnects and by which a proper seal is provided on the entry side of both walls.

A flexible hose 9 is provided by which chilled air from the heat exchanger assembly 6, and more specifically from rigid pipe 4 and 4A, installed in the refrigerated trailer 3, said chilled air, is supplied to the cab of the tractor 12, as illustrated in FIGS. 1 and 2, and detachable connector twist lock hardware, are secured to each end of the flexible hose 9, and 11. The blower motor in battery and blower box 13, and second flexible hose 10 is provided by which warm air from the cab of the tractor 12 is circulated to the back to the heat exchanger assembly 6, via and more specifically through flexible hose 11, and rigid pipe 2 and 2A, in the refrigerated trailer 3 as illustrated in FIG. 1.

The opposite end of the flexible hose is attached in like manner to a fitting in the rear wall of the tractor cab 12. An electronic switch, is connected into an electrical circuit, and is arranged on the instrument panel 14, inside the cab 12, by which the velocity of the heat exchange blower can be continuously adjusted. A second electronic switch (not shown) arranged on the instrument panel inside the cab is implemented to control the charging and operating state of the dedicated deep discharge battery.

It is, of course, common practice to use different tractors with different trailers, and the invention affords a ready means by which such interchange may be accomplished with a minimum of effort when desired.

The invention, while shown and described, is capable of being modified in structure and design without departing from the spirit and intent thereof or the scope of the intended claims. 

1. A cooling system for interior climate control of a trucking transport tractor comprising in combination: a. A transport trucking tractor vehicle; b. A refrigerated trailer unit; c. At least one fan blower motor to draw unchilled transport trucking vehicle cabin air at a constant volume, and force circulating air at a constant volume into a closed loop heat exchanger installed in a refrigerated trailer unit; d. A closed loop heat exchanger in a refrigerated trailer unit that thermally conducts refrigeration from the interior of an operating refrigerated trailer unit and generates chilled air at a constant volume into a transport trucking vehicle cabin; e. A detachable flexible air hose that circulates pressurized air at a constant volume connected at one end to the output of fan blower motor and at one end to a closed loop heat exchanger; f. A detachable flexible air hose that circulates chilled pressurized air connected at one end to a closed loop heat exchanger and at one end to and output opening in transport trucking vehicle; g. A detachable flexible air hose that circulates pressurized air connected at one end to an output opening of a transport trucking vehicle and at one end to the input of a fan blower motor; h. An electronic climate control switch to set on/off state and blower fan speed located inside the trucking tractor vehicle; i. At least one deep discharge battery dedicated to power the system; j. A guard assembly to cover and protect the heat exchanger from shifting goods and inventory during transport; k. An electronic control for monitoring the condition of deep discharge battery condition and charge/discharge operating state. 